Fetal Pig Dissection!

• Work in Groups of 3-4• Get out lab books and lab packets!

Fetal Pig Dissection – Day 1Getting Started!

Obtain the following materials:1 fetal pig per group

1 large dissection pan2 pieces of string - ~25-30 inches long

2 good scalpelsScissors

2 BLUNT ProbesForceps (tweezers)

Initial Prep

• Open up the plastic bag – – KEEP the outer bag AND the rubber band!– Cut open the inner bag over the sink. Empty

pig and contents into sink. THROW AWAY inner bag into the GREEN trash

• Rinse off pig well. Towel dry and place in a dissection tray

External Observations• Look for the umbilical cord

– Try to find the umbilical arteries/veins that connected its blood supply to mom via the placenta

• External nares (remember what those are?)

• Tongue • Boy or Girl?

– Look under the tail. • If all you see it an anus (hole)

then a SMOOTH swollen sac of skin – you have found the SCROTUM and you have a boy!

• If you see an anus (hole) plus an obvious folded area of skin. You have found the GENITAL PAPILLA and you have girl!

Scrotum

Anus

Genital Papilla

Anus

BOY!

GIRL!!!

Securing your Pig to the tray

• Use the 2 pieces of string to secure your pig to the dissecting tray

Incision Time1. Take a scalpel – make a

SUPERFICIAL midsaggital incision from chin to umbilical cord

2. Then use scissors to cut along either side of the umbilical cord to create a “flap”

3. & 4. Use scissors to make 2 lateral cuts. Avoid the staples on one side of the pig– Also be careful not to

demolish the DIAPHRAGM at the base of the rib cage!

Incision Time3. & 4. Use scissors

to make 2 lateral cuts. Avoid the staples on one side of the pig– Also be

careful not to demolish the DIAPHRAGM at the base of the rib cage!

Diaphragm

Separate Skin from rib cage• Using your scapel – separate the skin of the

chest area off of the rib cage.– You will have to cut through muscle and

connective tissue to do this– It’s like skinning raw chicken!

• Using scissors – cut of each half of the rib cage. You should end up with 2 large chunks of ribs in your tray

Diaphragm• Use scissors to separate

the diaphragm from the floor of the rib cage.

• You should be left with one big “flap” of Diaphragm that hangs over the liver and stomach (see d page 409 of lab book)

Diaphragm

Diaphragm

Exposing Larynx and Trachea – pg. 409• Using scissors – cut off any remaining pericardial

sac that might be covering the heart.– Place any pieces in your tray for later disposal

• Using a SHARP scalpel – remove all muscle and tissue overlying the larynx and trachea

Larynx

Trachea

Neck Blood Vessels – pg. 418 • Using a BLUNT PROBE – carefully probe on either

side of the trachea until you expose– 1 PINK common carotid artery on each side– 2 BLUE jugular veins on each side

• These are the internal and external jugular veins

Internal Jugular Vein

Common Carotid Artery

External Jugular Vein

Heart• Using a combination

of scalpel and scissors:– Cut off the

pericardial sac that surrounds the heart

– Be careful not to cut off any important blood vessels!

• Also not the texture and position of the RIGHT AND LEFT LUNGS.

Superior Vena Cava

Right LungLeft Lung

Cardiovascular System:Superior Vena Cava, Pulmonary Trunk & Aortic Arch

Superior Vena Cava

Right Lung Left Lung

Aortic ArchPulmonary Trunk

What now? Locate all Respiratory & Digestive System organs listed on Page 13 of your lab

packet!• Use pg. 404 & pg. 409 in your lab books for

help

• Note: do NOT find the urinary organs yet – we will do this later.

• When your group thinks it has found everything – call me over so I can review it with you!

Ready to clean up?• Cut off strings – throw away in GREEN trash.• Throw any PIG TISSUE WASTE in the RED trash

• Rinse pig under water and clean both external and internal areas.

• Spray pig with cavicide (in white spray bottle) inside and out!

• Put pig in your saved plastic bag and secure with rubber band.

• Write the pig’s name (or group name) on the bag in permanent marker.– Place bagged pig in the tray.

• Spray down your table with cavicide or simple green!

Respiratory System

• Make sure you can locate:– External nares– Larynx– Trachea– Diaphragm– lungs

Digestive System• Be sure you can locate:

– Tongue– Esophagus– Stomach– Liver– Gallbladder– Small intestine– Large Intestine– Pancreas– Mesentery– Rectum

Digestive System

Liver

Gallbladder

Small intestine

Large intestine

Mesentery

Rectum

Note: the following are not shown, but you need to know where they are:Tongue, esophagus, stomach, pancreas

Fetal Pig Dissection – Day 2

Urinary System• Do NOT cut out the

intestines to dissect the urinary system!

• Push the intestines to one side and use a scalpel or blunt probe to remove the connective tissue around each kidney and ureter

• Note the ALLANTOIC BLADDER

Right Kidney

Left Kidney

Right UreterLeft Ureter

Allantoic Bladder

Rectum

Reproductive System - MALE

Allantoic Bladder

testes

Penis

Spermatic Cord

EpididymisEpididymis

Spermatic Cord

testes

Reproductive System - FEMALE

Allantoic Bladder

Ovary

Ovary

Uterine Horn

Uterine Horn

Uterine Body

Cardiovascular System – Heart & Spleen

heart

Spleen

Cardiovascular System – page 418– 1 PINK common carotid artery on each side– 2 BLUE jugular veins on each side

• These are the internal and external jugular veins

Internal Jugular Vein

Common Carotid Artery

External Jugular Vein

Cardiovascular System:Superior Vena Cava, Pulmonary Trunk & Aortic Arch

Superior Vena Cava

Right Lung Left Lung

Aortic ArchPulmonary Trunk

Cardiovascular System:Inferior Vena Cava & Abdominal Aorta

Inferior Vena Cava

Small Intestine

Mesentery

Abdominal Aorta

Rectum

Ready to clean up?• Cut off strings – throw away in GREEN trash.• Throw any PIG TISSUE WASTE in the RED trash

• Rinse pig under water and clean both external and internal areas.

• Spray pig with cavicide (in white spray bottle) inside and out!

• Put pig in your saved plastic bag and secure with rubber band.

• Write the pig’s name (or group name) on the bag in permanent marker.– Place bagged pig in the tray.

• Spray down your table with cavicide or simple green!